Investigation into methods for improving antisera production against a variety of oral bacteria has been an area of continued research in our labortory. Streptococcus mutans serotype c has been of particular interest because of its prevalence in humans and, in general, poor immunogenicity in rabbits. Previous studies have examined different variables including immunization schedule, vaccine strain and vaccine dose in an attempt to produce the high titered antisera necessary for reagent grade fluorescent antibody conjugates. More recently, we have investigated the effect of slow, continal release of antigen into rabbits through use of Alzet minipumps.